Formation of oxides on CoCrMo surfaces at room temperature: An XPS study

We have studied the initial stages of oxide formation on CoCrMo surfaces, exposed to oxygen environment or bombarded by low-energy oxygen ions at room temperature (RT), using x-ray photoemission spectroscopy (XPS) around Co 2p, Cr 2p and Mo 3d core-levels. The results are compared with the oxidation of pure Co, Cr and Mo metals from the literature. While the oxidation of all three metals from CoCrMo in oxygen atmosphere follows the logarithmic growth kinetics, characteristic for the electric field driven migration of metal cations or oxygen anions, oxidation induced by low-energy oxygen ions follows the parabolic growth rate.